Try this: For an entire day, forget about the clock. Eat when you're hungry and sleep when you're tired. What do you think will happen?

    You may be surprised to find that your day is much like most other days. You'll probably get hungry when you normally eat and tired when you normally sleep. Even though you don't know what time it is, your body does.

    These patterns of daily life are called circadian rhythms, and they are more than just habits. Inside our bodies are several clocklike systems that follow a roughly 24-hour cycle. Throughout the day and night, our internal clocks direct changes in temperature, body chemicals, hunger, sleepiness and more.

    Everyone's rhythms are unique, which is why you might like to stay up late while your sister always wants to go to bed early. But overall, everyone is programmed to feel tired at night and energetic during the day.

    Scientists have known for a long time that the light of day and the dark of night play important roles in setting our internal（内部的） clocks. Now, new discoveries are giving scientists insights into how these clocks work.

    Learning about our body clocks may help scientists understand why problems arise when we act out of step with our circadian rhythms. For example, traveling across time zones can make people wake up in the middle of the night. Regularly staying up late can make kids do worse on tests and quizzes. And working shifts at night leads to higher rates of heart disease, diabetes and obesity.

    “There is a growing sense that when we eat and when we sleep are important parts of how healthy we are,” says Steven Shea, Director of the Sleep Disorders Research Program at Brigham and Women's Hospital in Boston.

    Scientists still aren't sure why the timing of sleep matters so much, Shea says. But research findings suggest that our circadian rhythms are more important than we give them credit for.

    “During the night, we are prepared to sleep,” Shea says. “During the day, we are prepared to eat and move around. If you reverse (颠倒)what you are doing, everything is out of phase. That can have unfavorable consequences.”

    My father's reaction to the bank building at 43rd Street and Fifth Avenue in New York city was immediate and definite: "You won't catch me putting my money in there!" he declared, "Not in that glass box !"

    Of course, my father is a gentleman of the old school, a member of the generation to whom a good deal of modern architecture is upsetting, but I am convinced that his negative response was not so much to the architecture as to a violation of his concept of the nature of money .

    In his generation money was thought of as a real commodity (实物)that could be carried, or stolen. Consequently, to attract the custom of a sensible man, a bank had to have heavy walls, barred windows, and bronze（青铜） doors, to affirm the fact, however untrue, that money would be safe inside. If a building's design made it appear impenetrable（难以渗透的）, the institution（公共机构, 协会, 制度）was necessarily reliable, and the meaning of the heavy wall as an architecture symbol dwelt in the prevailing attitude toward money.

    But the attitude toward money has, of course, changed. Excepting pocket money, cash of any kind is now rarely used; money as a tangible（切实，实在）commodity has largely been replaced by credit. A deficit (赤字) economy, accompanied by huge expansion, has led us to think of money as product of the creative imagination. The banker no longer offers us a safe: he offers us a service in which the most valuable element is the creativity for the invention of large numbers. It is in no way surprising, in view of this change in attitude, that we are witnessing the disappearance of the heavy-walled bank.

    Just as the older bank emphasized its strength, this bank by its architecture boasts of imaginative powers. From this point of view it is hard to say where architecture ends and human assertion (人们的说法)begins.

    A chip inserted in a young quadriplegic's (四肢麻痹患者) brain is already improving his quality of life. Soon the benefits may be more widespread.

    A 25-year-old man unable to move from the neck down recently did what many assumed impossible. After a knife attack that had left him paralyzed, all he could move was his head, which he used to push a switch and call for a nurse. And he could turn his wheelchair by blowing into a straw near his face. That was it.

    Then last June, a Foxborough (Mass.) company called Cyber Kinetics opened the man's skull and inserted a special chip no larger than a baby aspirin. That insert has given him a few additional and precious abilities. When connected to a special computer via a cable, the chip translates the young man's thoughts into commands that let him move a cursor across a PC screen and open e-mail. He can draw a circle with a computer painting program. And he can use a robotic hook(钩) to perform simple tasks like picking up a candy and sliding it across a table.

    All he has to do is to think.

    Several new studies have begun or been completed in the past year. In fact, more than half of the scientific papers in this field, called brain-to-computer interaction (BCI), have been published in the past two years, notes Jonathan Wolpaw, a research physician at Wadsworth Center, the New York State Health Dept.'s research laboratory.

    Brain surgeries (手术) are no longer rare: Thousands of Parkinson's disease patients have had special devices inserted in their brains to ease uncontrollable shaking and other symptoms. The inserts themselves have improved, so the body doesn't reject them as furiously(猛烈地). And significant development has been achieved in software used to interpret the brain's signals and change them into commands understood by computers.

    But increased demand for thought technology remains the biggest reason for the field's progress. Today, 4 million Americans live with paralysis according to the Christopher Reeve Paralysis Foundation.

    Scientists hope that thought technology will reduce the impact of such disabilities. People with spinal-cord injuries, for example, often lose their ability to walk because the communications network between their brain and their legs has been interrupted. The brain still commands the leg muscles to move, but they don't hear its orders.

    Thought technology, scientists hope, will bridge this communications gap. "Our goal is for you to see paralyzed people eating at a restaurant and for you not to know that they are paralyzed," says John Donoghue, founder and chief scientific officer at Cyber Kinetics.

    Against the assumption that forest fires in Alaska, Canada and Siberia warm the climate, scientists have discovered that cooling may occur in areas where burnt trees allow more snow to mirror more sunlight into space.

    This finding suggests that taking steps to prevent northern forest fires to limit the release of greenhouse gases may warm the climate in northern regions. Usually large fires destroyed forests in these areas over the past decade. Scientists predict that with climate warming, fires may occur more frequently over next several centuries as a result of a longer fire season. Sunlight taken in by the earth tends to cause warming, while heat mirrored back into space tends to cause cooling.

    This is the first study to analyze all aspects of how northern fires influence climate. Earlier studies by other scientists have suggested that fire in northern regions speed up climate warming because greenhouse gases from burning trees and plants are released into the atmosphere and thus trap heat.

    Scientists found that right after the fire, large amounts of greenhouse gases entered the atmosphere and caused warming. Ozone（臭氧）levels increased, and ash from the fire fell on far-off sea ice, darkening the surface and causing more radiation from the sun to be taken in. The following spring, however, the land within the area of the fire was brighter than before the fire, because fewer trees covered the ground. Snow on the ground mirrored more sunlight back into space, leading to cooling.

    “We need to find out all possible ways to reduce the growth of greenhouse gases in the atmosphere.” Scientists tracked the change in amount of radiation entering and leaving the climate system as a result of the fire, and found a measurement closely related to the global air temperature. Typically, fire in northern regions occurs in the same area every 80 to 150 years. Scientists, however, found that when fire occurs more frequently, more radiation is lost from the earth and cooling results. Specifically, they determined when fire returns 20 years earlier than predicated, 0.5 watts per square meter of area burned are soaked up by the earth from greenhouse gases, but 0.9 watts per square meter will be sent back into space. The net effect is cooling. Watts are used to measure the rate at which energy is gained or lost from the earth.

    Kunta wondered why the white people had done this to him. Born a free man, he was now in chains. Heavy iron chains around his feet and hands were fixed to a metal bar that ran round the hall about ten centimeters off the ground. He was just able to lie down on the ground, but could not stand up.

    Kunta had been seized in the forest and then hit on the head with a hard object. When he woke up, his hands and feet had already been tied together. What shocked him most was that the men who carried him were black. He reasoned with them, and tried to persuade them to set him free. But they would not listen to him. When they came to the river, a white man was waiting in the boat for them. There was an argument about money, so it seemed, in a language that Kunta did not understand. Finally, Kunta was thrown into the bottom of the boat and covered with an old smelly cloth. The men took him in their boat to the castle on the coast where he was now held prisoner.

    Another thing which shocked Kunta was that women were held in the castle too. He could hear their crying, also children's voices. What was to become of them all, he wondered. For all his life, he had known that people suddenly disappeared from their villages. He had known that it was not safe to travel alone in the forest near the coast. But why did white people want to catch Africans and put them in chains? Would they be killed or even eaten? The situation seemed hopeless and he knew his life was in danger.

    Worse was to come. A few days later about 140 black people were taken and put on a tall sailing ship waiting off the coast. Once on the boat, they were taken below and their chains were fixed to two bars that ran the length of the ship. Their feet were fixed to one bar and their hands to another bar. Thus they lay on hard wooden boards, unable to stand up or move around.

    The sea journey lasted over sixty days and nights. They had rough weather and Kunta's back bled from rolling over on the hard wooden boards. Many of the men fell sick with fever. They sighed and cried out for more water, but food and water were only given out once a day. Once in a while sailors came down, Kunta thought, to carry sick men upstairs for treatment. When the ship finally arrived in a port, the wooden cover was opened wide and Kunta could see in daylight for the first time across the part of the ship where he had been chained. About a third of the people who had been chained up below at the beginning of the journey were missing.

—Yes，and what a pity！It will be a long time ________ we see each other again.

    If you think your woman would never lie to you, guess again. From little 1 lies to the more serious variety, most women will hold back the 2 at some point in a relationship. Her motivation 3 lying can stem (起源于) from wanting to protect your feelings or, sure enough, to save her own butt (抵触).

    One day, when a seamstress（女裁缝师）was sewing 4 sitting close to a river, her thimble（顶针）fell into the river. When she cried out, the Lord 5 and asked, ‘My dear child, why are you crying?' The seamstress replied that her thimble had fallen into the water and 6 she needed it to help her husband in making a living for their family. The Lord dipped his hand into the water and 7 a golden thimble set with sapphires(蓝宝石).

    “Is this your thimble?” the Lord asked. The seamstress replied, ‘No.'The Lord again dipped into the river. He 8 a silver thimble.

    “Is this your thimble?” the Lord asked. Again, the seamstress replied, “No.”

    The Lord 9 down again and came up with a leather thimble.

    “Is this your thimble?” the Lord asked. The seamstress replied, “Yes.” The Lord was pleased with the woman's 10 and gave her all three thimbles to keep, and the seamstress went home, much 11 .

    Some years later, the seamstress was walking with her husband along the 12, and her husband fell into the river and disappeared under the water. 13 she cried out, the Lord appeared and asked her, “Why are you crying?”“Oh Lord, my husband has fallen into the river!”

    The Lord went down into the water and came up with George Clooney. “Is this your husband?”the Lord asked.

    “Yes” cried the seamstress. The Lord was 14. “You lied!” ”That is a(n) 15 !” The seamstress replied, ‘Oh, forgive me, my Lord. It is a 16. You see, if I had said ‘no' to George Clooney, you would have come up with Brad Pitt. Then if I said ‘no' to him, you would have come up with my husband. Had I then said “yes,” you would have given me 17. Lord, I'm not in the best of health and 18 be able to take care of all three husbands, 19 THAT'S why I said “yes” to George Clooney.'

    And so the Lord let her keep him.

    The 20 of this story is: Whenever a woman lies, it's for a good and honorable reason, and in the best interest of others.

Dear editor,

    According to a recent news report, in Chongqing City, there are a great number of students who abandoned opportunities to receive further education in college.

Yours'

Li Hua